As is known, an ischemic heart disease is a disorder in the heart which is caused when the flow of blood to the cardiac muscle becomes insufficient or is stopped by being blocked by occlusion, constriction, or the like of a coronary artery. The symptoms of this disease include pain and a feeling of tightness mainly in the precordium and sometimes in the left arm or back.
An FFR (Fractional Flow Reserve) is an index for determining whether the cardiac muscle is in an ischemic state due to a coronary stenosis. As shown in FIG. 9, a pressure wire is inserted into a blood vessel of an object to measure an upstream pressure Pin and a downstream pressure Pout of a constricted portion. The above index is defined as FFR=Pout/Pin.
In general, if the FFR value is less than 0.8 (serious condition), the patient requires a surgical treatment (PCI: Percutaneous Coronary Intervention), whereas if the FFR value is more than 0.8, the doctor often chooses a medicinal treatment. Since FFR measurement using a pressure wire is invasive, demands have arisen for non-invasive measurement/calculation methods.
Under the circumstances, a simulation-based measurement method using fluid analysis has recently been proposed.
This simulation is a three-dimensional simulation. The basic concept of simulation-based measurement is that an FFR is obtained by calculating a pressure using the Navier-Stokes equations, which are generally used in CFD (Computational Fluid Dynamics), using as inputs physical parameters such as the hardness of a blood vessel wall and the blood inflow rate calculated from contrast images.
Simulation-based measurement, however, requires time-series volume data throughout at least one heartbeat, and hence it takes much labor and time to perform imaging and data analysis. In addition, in a cardiac phase in which the heart moves fast, an image of a coronary artery sometimes blurs. There is therefore a possibility that data may contain an error.